1. Field of the Invention
The present invention relates to a method for controlling volume of a communication terminal and an apparatus for performing the method. More particularly, the present invention relates to a method for automatically controlling volume so that sending volume and receiving volume are equal in accordance with a communication network accessed at a communication terminal, and an apparatus for performing the method.
2. Description of the Related Art
A mobile communication system in a code division multiple access (CDMA) method has been developed into a second-generation digital technology from a first-generation analog technology. The second-generation mobile communication system has been developed into time division multiple access (TDMA) such as a global system for mobile communication (GSM) and into CDMA. In this instance, TDMA is usually used in European countries, China, a part of the United States, and so on. Also, CDMA is usually used in the United States and Asia-Pacific regions such as Korea, Australia, and the like. Also, as mobile communication services including a concept of personal communication services (PCS) have been commercialized all over the world since the latter half of the 1990's, mobile communication markets have also dramatically grown into a major business. The second-generation mobile communication system has advantages such as stabilized services, inexpensive fares, and the like. Owing to the advantages, mobile telephone services became very popular among general people. However, the second-generation mobile communication system has disadvantages such as services limited to voice calls, service availability limited to a nation or a provider.
To overcome the limits caused by the above technology and frequency band, and to provide multimedia services through faster transmission, International Mobile Telecommunication 2000 (IMT-2000) has appeared as a third-generation mobile communication service. Namely, IMT-2000 enables a user to readily send and receive multimedia information such as voice, image, and data with a party that the user wants, without restriction to time and place, in other words, across the world.
When IMT-2000 is finally fully utilized, multimedia services such as the Internet and image transmission may be provided in a better mobile environment via a super-high speed wired/wireless converged network. Also, IMT-2000 provides global roaming service in which one terminal may be used in any part of the world.
However, domestically, commercialization of IMT-2000 service is being delayed because of mobile communication service providers and other circumstances. CDMA 1x, known as 2.5-generation, mobile communication is being widely used.
An interim standard (IS)-95A/B is a second-generation (hereinafter, “2G”) mobile communication system and has a maximum data transmission speed of 64 Kbps. CDMA-2000 1X or (IS)-95C is a 2.5-generation (hereinafter, “1X”) mobile communication system and has a maximum data transmission speed of 307 Kbps. The 2G and the 1X mobile communication systems are being used together. Currently, 2G network, that is, IS-95A/B network has been spread nationwide. Also, 1X network, that is, IS-95C network has been laid over the IS-95A/B. Accordingly, when a position of a mobile communication terminal is registered to a mobile communication system using CDMA, the registration is performed by classifying the mobile communication terminal in the 2G network system and the 1X network system. The 2G network system mainly provides voice service, and the 1X network system mainly provides data service. Since most users of mobile communication terminals usually use voice service rather than data service, they subscribe to a provider with a 2G network system.
In the case of testing a conventional mobile communication terminal, the volume when a user accesses the 1X network is larger than the volume when the user accesses the 2G network. Accordingly, Vpp and power also increases and a receiver may be seriously damaged, which may cause a malfunction in a mobile communication terminal.
Also, volume gain set in an accessed communication network such as the 1X network or the 2G network is different and applied differently from volume gain set internally. Accordingly, a user may feel the difference between sending volume and receiving volume.
In the case of a receiver used in a conventional mobile communication terminal is normally about Typical 20 mW and Max 30 mW, when volume gain is set for the 2G network, sound may be too loud and be harsh to the ear in the 1X network. Also, since noise increases as gain increase, a user may find difficulty in communicating.
Namely, in the case of a conventional mobile communication terminal, sending volume and receiving volume is different according to an accessed network. Accordingly, every time a communication network accessed by a user is changed, the user has to adjust the volume.
Accordingly, a communication terminal needs a function of maintaining sending volume and receiving volume to be equal, irrespective of whether an accessed communication network is 1X network or 2G network.